I currently manage a hosting server. What POP3/SMTP combination would you recomend for virtual hosts? We currently use Sendmail with teapop. teapop uses the .procmailrc file in the user's home directory. It works really well, except there's a bug which can cause the owner of the list to recieve 20+ of the same e-mail (it goes into a mailing loop). Our requirements are that multiple domains are supported, and that both the system usernames (based upon the system's domain name) are used for POP3, and that each domain can have its own list of aliases and pop3s which can also match the system's usernames.
I am currently looking into pop3lite and DMail as alternatives